The present invention concerns a ballistic grill used in special vehicles such as armored vehicles and especially a ballistic grill to protect a vehicle effectively from bullets and splinters with minimized weight.
Special vehicles usually have their engine compartments with cooling systems enclosed with a capsule member to prevent the vehicle from malfunctioning due to damage caused by penetration of a bullet or splinters. Normally, the essential air for combustion and cooling is supplied and removed through an inlet opening and an outlet opening.
Furthermore, the ballistic grills should be installed to cover inlet and outlet openings to prevent penetration of bullet into the engine compartment.
The requirement of a ballistic grill is to prevent penetration by bullets or splinters effectively, and to maximize air channels to cover necessary airflow with minimized weight for the entire system.
German Patent OS 37 03 716 uses a ballistic grill system as one of former technologies. In this patent, the ballistic grill includes several profile moldings manufactured with structural steel. And additional whole or partial profile parts are attached at the end of each profile moldings toward the vehicle at an angle aimed at preventing bullets or splinters.
In this kind of ballistic grill, since profile molding and profile parts are made mostly of steel, there is much possibility of creating splinters when it is hit by a bullet, and those splinters can penetrate. Sometimes, the bullet possibly penetrates the profile molding to reach the engine compartment.
Also, German Patent 4015 304 A1 discloses profile moldings made of a minimum of two individual profiles which create a hollow space. This hollow space can be filled with sandwich elements. An upper individual profile is made of metal or metal alloy with lower hardness and high elongation and a lower individual profile is made of metal or metal alloy with high hardness and lower elongation. Therefore, this can absorb the kinetic energy of a bullet, and a bullet that has penetrated through the upper profile can be caught in the hollow space. This type of grill improves the protection level by minimizing fragments.
However, in the preceding Korean Patent Application No. 91-7591, even though the upper profile is made of material with lower hardness and high elongation, it is made of metal basically and has limited capability in shock absorption and protection. Furthermore, there is difficulty in reducing the weight of the entire system, since both individual profiles are made of metal.